Patent GB-110369-A (GB)
Title: Improvements in and relating to Gyroscopic Compasses.
Inventor: HENDERSON JAMES BLACKLOCK
IPC: G01C19/38
Filed: 1916-07-12
Abstract: 110,369. Henderson, J. B. July 12, 1916. Gyroscopic compasses.-In a gyroscopic compass having a pendular system which is practically in neutral equilibrium in the E-W vertical plane, a spring control is provided to fix the normal position of the pendular system; a damping-device forming part of the pendular system may also be utilized to damp the oscillations of the compass about the meridian. Fig. 4 shows such a pendular system applied to a compass having two gyroscopes, the system being as described in Specification 16098/15. A spring 30 is provided which connects the system to the case of the lower gyroscope. The period of the system in the E-W vertical plane due to the spring is lengthened by means of a small gyroscope 32 in the bob of the lower pendulum, the gyroscope 32 being mounted on trunnions 33 and being constrained by springs 34. The pendular system may be damped in the E-W plane by friction on the trunnion axis of the gyroscope 32. Fig. 2 shows a compass having a single gyroscope and a pendular system of the type referred to. The system comprises a pendulum 1 supported on an axis 4 projecting from the gyroscope casing 21 and two pendulums 1<1> attached to a spindle 4<1> which is either mounted in the gimbal ring 24, as shown, or in brackets attached to the plate 14 of the following element. The pendulums are rigidly connected to frames 5, 5<1> respectively, and the frames are connected by links 6, 7 which permit relative movement between the pendulums in the meridian. The pendulum 1 is connected by a spring 30 to the casing of the gyroscope. The system is damped in the E-W vertical plane by making the bob of the pendulum 1 hollow and almost completely filling it with a viscous fluid, or by similarly treating the bobs of all the pendulums. An apertured central diaphragm may be provided in the bob of the pendulum 1 to damp the oscillations of the compass about the meridian. Fig. 5 shows a compass of the Sperry type in which the bail weight 35 is connected to the casing of the gyroscope by a rigid frame 38 pivoted on an axis 4 coaxial with the rotor axis and carrying a roller 41 engaging in a roller path in the bail weight. The frame 38 carries a gyroscope 32 mounted as described in connexion with Fig. 4, and a balance. weight 39 which may be in the form of a transformer for reducing the voltage supplied to the gyrcscope 32. The frame 38 is connected by a spring 30 to the casing of the gyroscope so that it is normally constrained in a position in which the roller 41 lies to the east of the vertical centre line of the casing of the gyroscope. According to Provisional Specification 11528/16, the frame 38 may carry two gyroscopes. According to Provisional Specification 9813/16, a compass may be provided with two directing gyroscopes having their rotor axes inclined to each other and so linked together and to the pendulums that they provide the vertical increase of inertia to the pendular system in the E-W vertical plane. Specifications 26160/13 and 10095/14 also are referred to.